* Java SDK: Rewrite the user docs around Dag definition
Reorder the Java SDK guide to start from a Dag defined in Java, document
conditions, switches and TriggerDagRun, and add a table of how stub task
arguments bind. Split the README into a user landing page and
DEVELOPMENT.md, and add an example README.
* Add Logback and appender to the docs spelling wordlist
* Address review: Dag-level queue, version sync, dropped constraints
Set the queue once on the Dag in every example, now that a Java Dag takes
one, and bump the documented version to 1.0.0-beta2 everywhere. Add a prek
hook that fails when the guide, the README and the Dokka landing page name
different versions. Restore the TaskInput constraints, correct the
LocalExecutor wording, and drop the Python Label comparison.
* Generate the quick start of the Java SDK README and Dokka page
The quick start appears on three pages. The guide owns it now, between
SHARED SNIPPET markers, and the sync-java-sdk-docs hook copies it into the
other two and still checks that all three install the same version.
* Address review: install a version placeholder, not a release
The three pages that show how to install the SDK pinned a release that is
not out yet, which also held the PR back. They now install `<version>` and
link to Maven Central, and the sync hook fails when a page names a release
instead. The parse-failure bullet leads with the SDK release a JAR was built
with, and keeps the supervisor schema version as the explanation.
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Jason(Zhe-You) Liu
Tzu-ping Chung